A new CDC study finds that mRNA COVID-19 vaccines are highly effective in preventing COVID-19 among health care and other essential workers, groups more likely to be exposed to the virus because of their
occupations. The study found that “partial” vaccination (two weeks after a single dose) with either a Pfizer-BioNTech or Moderna vaccine reduced the risk of infection by 80%. “Full” vaccination (two weeks after the second dose) reduced risk of infection by 90%. It takes about two weeks following each dose of vaccine for antibodies that protect against COVID-19 to develop. Learn more: bit.ly/MMWR32921.